Communication method and apparatus for use in a computing network environment having high performance LAN connections

ABSTRACT

A method and apparatus for establishing communication between a first initiating host and a second communicating host in a computing environment having a gateway device. The gateway device is electronically connected from one side to a plurality of initiating hosts and on another side to at least one local area network, further connecting a plurality of receiving hosts to said gateway device. During an initialization step, all connected hosts and the local area network(s) is identified and their addresses and information obtained and stored in a port-sharing table in a memory location accessible to the gateway device. Upon receipt of a special command for establishing communication between a first initiating host and a second receiving host, all information required for establishing of a successful communication between the two hosts is then obtained from the port-sharing table. In an alternate embodiment of the present invention the computing network environment uses Multi-path channel communication protocol.

FIELD OF INVENTION

The present invention is generally directed to an expanded controlcommand interface that can support network connections to gatewaydevices without dealing with configuration complexities.

BACKGROUND OF THE INVENTION

Personal computers are gaining widespread popularity as the state oftechnology is improving. Over the past few decades, their utilizationhas profilerated both for personal purposes and for use in business andscientific communities. Establishing good computing communications havebecome a necessity as individual users try to connect to one another forexchange of information, and to larger computers to take advantage oftheir higher processing capabilities. This need to communicate betweendifferent computing hosts or nodes have evolved into the creation ofdistributed networks. A distributed network is an aggregate ofindividual systems that are connected to one another electronically.Distributed networks can be organized in a number of ways, eitherremotely extending over great distances using wide area networks orWANs, or locally through the use of a Local Area Network, better knownas a LAN.

A LAN usually consists of a number of nodes or hosts located within anoffice, a building or at other close proximations. Being a type of adistributed network, a LAN loosely couples processors and workstations.Generally, workstations on a LAN do not share a central memory but doshare common servers. In this way a LAN increases the power andflexibility of workstations by enabling them to access shared datawithout jeopardizing the security of each individual resource.

A LAN system that has been in wide use in recent years is produced byNovell, Inc. of Provo, Utah. In a Novell system, a LAN device driver isimplemented on top of the local operating systems to be coupled anddevice driver commands at the LAN workstations are directed to and fromthe workstations onto the LAN to the target servers.

As networks have grown and particularly as LANs have come intowidespread use, many businesses and organizations have faced thenecessity of interconnecting and managing a confederation of networksand LANs. Each network itself can in turn comprises of a plurality oflogical networks which in turn run independent and different networkingprotocols. The challenge has not become only to interconnect local areanetworks to one another, but to do so and still provide remote serveraccess through WANs or other devices.

Three basic methods are now available to interconnect both local andremote area networks to one another as to provide wide used access andremote information exchange capabilities. These three methods are 1)bridges or data-link devices that connect similar networks together; 2)routers that perform routing services by maintaining a routing table ineach host; and 3) gateway devices that carry out protocol conversionsand other connectivity functions. Typically, a device driver for thegateway is provided with modems or other physical ports that can belinked to switched communication WANS.

A gateway facility allows the interconnection of multiple independentlycontrolled communication networks to one another in a way that logicalunits in the network can communicate with one another without anychanges to the network. A logical network runs a single networkingprotocol, but a processing organization can be composed of a dozen oflogical networks running six or seven networking protocols. A gatewayprovides transparent interconnection of these single networkingprotocols, so that a single multiport transport network is formed.

In the existing mechanisms, gateway devices are implemented on top ofthe LAN device drivers as a switched communications device interface.The user initialization of the communication link-up procedure redirectsthe user hardware commands to the gateway. The communications interfacein the gateway driver then institutes and maintains the switchedcommunications link, diverting hardware resources of the driver to doso. The connection and access procedures are then executed using thegateway ports and modems in order to link the user's system with theswitched communications network. A remote connection is establishedthrough the LAN/WAN which sets up a point to point configuration throughthe port along the communication line between the user and thecommunications device in use.

The procedure described above have many complexities associated with it.The complexities connected with the configuration assessment of gatewaydevices is an on-going concern of the designers of such devices today.These configuration concerns contributes to many limitations that existwith today gateway devices. These limitations often make theinterconnection of networks running different protocols non-transparent.Because many of the present gateways are transport layerprotocol-specific, it is possible that a gateway cannot interconnect anetwork running for example a TCP/IP protocol and a network running theSNA protocol. Furthermore, a variety of gateway devices have beendeveloped which connect TCP/IP to different operating system and giveconnectivity to the LAN/WAN environments, but each time theconfiguration has to be redefined and reassessed before connectivity isaccomplished successfully. Furthermore, each gateway device can usuallyimplement only a subset of the TCP/IP functions. Most currently existinggateway devices do not support many of the TCP/IP functions andperformance problems have been encountered due to increased bandwidth ofthe LAN/WAN arenas. One of the communication protocols used tocommunicate with the gateway is LCS or LAN Channel Station. A controlcommand interface exists in the LCS protocol that requires all theconfiguration information to be set prior to the TCP/IP connectsequence. Nonetheless, the control interface does not have a commandsequence to enable the use of the TCP/IP functions which have beenimplemented in the gateway devices. To reduce the complexity ofconfiguring gateway devices, an expanded control command interface isneeded.

This application is being filed with the following related applicationson the same date—attorney dockets: P09-97-097; P09-97-098; P09-97-127;P09-97-128; P09-97-129; P09-97-130; P09-97-140; P09-97-141; P09-97-142;and P09-97-143; and P09-97-144.

SUMMARY OF THE INVENTION

A method and apparatus for establishing communication between a firstinitiating host and a second communicating host in a computingenvironment having a gateway device. The gateway device iselectronically connected from one side to a plurality of initiatinghosts and on another side to at least one local area network, where thelocal area network further electrically connects a plurality ofreceiving hosts to said gateway device. During the initialization, allconnected hosts and the local area network(s) is identified and alltheir information and addresses are obtained so that this informationcan be stored in the form of a port-sharing table in a memory locationaccessible to the gateway device. Upon receipt of a special command forestablishing communication between a first initiating host and a secondreceiving host, all information required for establishing of asuccessful communication between the two hosts is then obtained from theport-sharing table. In an alternate embodiment of the present inventionthe computing network environment uses Multi-path channel communicationprotocol.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter which is regarded as the invention is particularlypointed out and distinctly claimed in the concluding portion of thespecification. The invention, however, both as to organization andmethod of practice, together with further objects and advantagesthereof, may best be understood by reference to the followingdescription taken in connection with the accompanying drawings in which:

FIG. 1 is a block diagram illustration of a computing environment;

FIG. 2 is another block diagram illustration of a computing environmenthaving a gateway device and a plurality of hosts;

FIG. 3 is another illustration of the block diagram shown in FIG. 2 witharrows indicating the existing flow of information;

FIG. 4 is another illustration of the block diagram shown in FIG. 2 witharrows indicating the flow of information according to one embodiment ofthe present invention;

FIG. 5 is yet another block diagram illustration of a computingenvironment providing different functions as supported by theenvironment;

FIG. 6 is an illustration of blocks of data grouped together; and

FIGS. 7A and 7B is an illustration of data flow to and from the gatewaydevice.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is an illustration of an example showing the connection of largecomputing network environment, such as one provided by a large mainframecomputer, to a Local Area Network (LAN) and the Internet. The largerectangle in FIG. 1 shown at 100 is a computing network environment suchas an IBM S/390 computer. The operating system(s) for the computingenvironment is shown as 110 and can be one of many available operatingsystems such as OS/390 or MVS/ESA. At the next layer, shown at 120, thesoftware products and applications reside, some examples being DB2, TSO,CICS, and IMS. The Common Gateway Interface or CGI is shown at 130 andinterfaces with the communication devices such as an IBM InternetConnection Server, to access VTAM (shown at 142), TCP/IP (shown at 144),IPX (shown at 146) or other similar communication protocols. The networkconnection to the LAN and/or Internet (shown at 160-174) can beaccomplished by means of any indicated communications controller or suchas an Open Systems Adapter connection, hereinafter OSA. The networkconnection from the computing environment servers can be a channel (150)or an integrated platform (155) connection. An Open System Adapter or anOSA shown at 158 is an integrated connectivity platform and a product ofIBM Corp. of Armonk. OSA provides direct attachment to token ring (shownat 172), ethernet (shown at 174), FDDI's or fiber distributed datainterfaces, and ATM (not shown). Multiple host systems can be accessedfrom a single workstation through a single OSA LAN/WAN port. Integratedon the OSA card is a channel adapter, a control unit and LAN adapters.OSA supports a variety of communication protocols, namely SNA/APPN,TCP/IP and IPX. OSA allows the sharing of applications and/or LAN portsamong logical partitions.

There are many protocols used to connect the communication stacks, forexample an MVS TCP/IP Stack to a channel attached platform or anintegrated platform such as the OSA. One such platform protocol is knownas an LCS or LAN Channel Station. LCS provides an efficient method oftransferring data across the I/O subsystems by blocking multiple LANframes together in one common chain. In the following sections, theteachings of the present invention may be described in reference with asystem using OSA and LCS to communicate with the MVS operating system ina setup using TCP/IP. However, the workings of the present invention isnot limited to the use of OSA, LCS, TCP/IP and MVS and any suchreference will be used for demonstrative purposes only.

A variety of gateway devices have been developed which connect to TCP/IPand give connectivity to LAN/WAN environment. In the existing systems,when a host is communicating with a LAN or other similar networks aMedia Access Control Header, also known as a MAC Header, along with theLAN type, has to be first established so that the host and the LANunderstand what kind of device and at what address the communication isbeing determined to address the particular needs of one another.Building a MAC header is not an easy task. In a large communicatingenvironment, each time the host and LAN devices communicate a MAC Headerhas to be created which can be both inefficient in terms of time andmemory consumption. Each time communication is to be establishedinformation including the device(s) address on both the sending andreceiving ends, MAC header, LAN type, device type, protocol versioningand the like has to be exchanged. This process requires substantialspending of both time and memory. The present invention, however,introduces a concept which makes the formation of MAC headers andproviding of such aforementioned information each time between theinitiating host and receiving device obsolete. This will save latency,memory capacity and introduces efficiency on memory moves especially onthe initiating host's side. The host no longer has a requirement to knowany LAN/WAN specific information.

FIG. 2 depicts one embodiment of the present invention. Originatinghosts A and B shown at 210 and 212 are connected to a gateway device,preferably an integrated gateway device such as an OSA and shown at 220.The destination hosts C and D shown at 240 and 242 are also connectedvia the LAN shown at 230 to the gateway device. In the existing systemswhen originating hosts A and B try to establish communication withdestination hosts C and D, the appropriate MAC Header has to be formedfirst for each communication. Another existing limitation in the presentsystem is that if host A is trying to communicate with host B, theinformation has to travel from host A into the gateway device and ontothe LAN as depicted by the arrows shown in FIG. 3 at 350 before beingtransformed to Host B. The present invention, however, provides for atechnique so that the information from Host A can be provided to Host Bwithout going to the LAN at all as depicted in FIG. 4 and indicated bythe arrows shown at 460.

In the present invention whenever each host gets connected to thegateway device, it sends the required address information as anconfiguration command to the gateway device during an initialhandshaking at the onset of establishing communication with the gatewaydevice. It is the gateway device itself that uses the configurationcommand and controls the communication from that point on. Referringback to FIG. 2, destination hosts C and D continuously are aware of theIP addresses and requirements of the gateway device. Destination hosts Cand D obtain the destination MAC addresses of initiating hosts A and Bdirectly from the gateway device, not from Hosts A and B. Hosts A and Bhave no knowledge of the media specific information or addressresolution. Hosts C and D only know about the gateway device address. Inother words hosts C and D only know hosts A and B through the gatewaydevice. The same is true about hosts A and B in that they are not awareof independent existence of C and D except through the use of thegateway device. As a consequence, there is no need to define the type ofdevice or the LAN type and protocol versioning each time thecommunication is being established. In the present invention there aretables existing in the gateway device that are used to make the deviceaware of all the host/LAN/WAN connections and their special needs. Everytime, for example host A is trying to communicate with host C, thegateway device searches in its table of addresses to find the address ofA and C so that communication is carried out successfully. But thegateway device is also aware, through the use of its previously storedinformation of the type of LAN that is connected to device C, anylimitations and particular needs that device C has as well as the typeof communication protocol needed for device A to communicate with deviceC. Every time a LAN or host is being newly added, the present inventionthrough an initialization step introduces the device and stores anypertinent information that is needed for further communications. Fromthat point on, once the host becomes connected to the gateway device,the gateway device remains aware of all its requirements. The gatewaydevice also checks the availability and existence of the deviceconnections and their workability, at intervals to monitor and ensurethat the device is still available. If the device is no longer in use,the gateway device makes the appropriate alterations to the table(s) inquestion.

In the existing systems there is a configuration file attached to eachcommunication platform that controls all configuration information. Itis the responsibility of the user to keep this configuration fileupdated. Any new addition or deletion of hosts must be inputted by theuser and there is no way that modifications and alterations can behandled automatically. The present invention, however, as explainedearlier dynamically and automatically handles alterations, additions andmodifications to the configuration through the use of commands explainedin detail below and through the use of specially accessed tables.

FIG. 5 is an illustration of the workings of the present invention asexplained by one embodiment. The host and its operating system andapplications is shown at 500 and 501 respectively. The IP protocols areshown at 502 (IP) and TCP and UDP at 504 and 506, respectively. TheTCP/IP or UDP/IP functions available are shown at 550—ARP, 552—InboundTCP checksum, 554—IP fragmentation/reassembly, 556—broadcast filtering,558—IP multicast, 560—Inbound UDP checksum and 562—IP version support(Version 6 is used as way of example). The communication protocoloptions presented at 550-562 are merely for demonstration purposes andit is possible to add or modify this list according to each particularsetup and mechanism. For example in an alternate embodiment of theinvention described below, SAP and RIP functions are among the functionsthat are supported. The LAN connection is shown at 580 and the gatewayconnection at 530.

In such setups, usually a control command interface exists in thegateway device to allow TCP/IP or other protocols to connect to thegateway device in order to begin data transfers. However, this controlcommand interface requires all the configuration information to be setprior to the TCP/IP connect sequence. Furthermore, the control interfacedoes not have a command sequence to enable the use of the TCP/IPfunctions which have been implemented in the gateway device. The TCP/IPprogram product running on such operating systems as MVS and VM/VSE havebeen developed by a number of companies. But many of today's TCP/IPimplementations have encountered performance problems due to theincreased bandwidth of the LAN/WAN arenas. To try and improve the MVSand other similar operating system's performance using TCP/IP or othercommunication protocols, various TCP/IP functions have been identifiedwhich could better be implemented in a gateway device which has LAN/WANconnectivity. Some of these functions include ARP assist, TCP and IPchecksum calculations, broadcast filtering and IP fragmentation andreassembly. To reduce the complexity of configuring the gateway devices,the present invention introduces an expanded control command interface.This will allow gateway devices to implement most TCP/IP functions andprovide means for determining which TCP/IP functions are supported bythe gateway device, if any.

The present invention provides for an expanded control command interfaceto reduce the complexity of gateway device configurations and addressthe limitations caused by providing a MAC header. A new subset ofcontrol commands have been developed which can be used to reduce suchconfiguration complexities. These fall into three basic categories.

The Set IP Address function basically sets up the IP address at STARTUPtime, instead of configuration time. In this way each time a TCP/IPsession has to be initialized, configuration needs not to bereestablished, therefore reducing the complexity of configuring thedevice and dynamically configuring the new IP sessions.

Query IP Assist function allows the TCP-UDP/IP to query the channelattached device to determine which TCP-UDP/IP functions are implementedin the device. This will allow the ability to determine which functionsif any it wishes to use on the gateway device. So referring back to FIG.1, all functions shown at 150-162 may not be available. Rather only asubset of 150, 152 and 154 may be available. If the user requires the IPmulticast, for example, which is not available the Query IP Assist willallow the user to determine this before further processing time iswasted. Because of its flexibility, the Query IP Assist function can beselected as desired to either work in conjunction with the SET IPAddress function or with SET IP Assist function.

The Set IP Assist function will tell the channel attached device whichTCP-UDP/IP functions are supported and available to be activated. Thisallows TCP-UDP/IP to individually select which functions it desires touse. Referring back to FIG. 1, the user may only want to selectbroadcast filtering for example from the menu of available functionsshown at 152-162.

As a consequence, as explained earlier, since the hosts really only knoweach other through the gateway device, and the gateway device throughits port-sharing tables controls and monitors all the configurationinformation, when Host A wants to communicate with Host B, (FIGS. 2-4),Host A's data does not require to go all the way to the LAN before beingtransmitted to Host B as in the existing systems. Routing between A andB is direct and without the extra step of involving the LAN. Thisrouting mechanism can be implemented in a loosely coupled environment,such as a Sysplex, for sending any type of data between any two hostsand especially without involving any LAN/WAN connections.

Set IP Address

The Set IP Address command is used to associate an IP address with aspecific user session. The command is initiated by the user. Once thecommand is received, the gateway device quickly searches its existingport-sharing tables to see if the particular IP address is included ornot. If there is a match found, that means that the particular devicehas been formerly identified. A complete IP data match also indicatesthat there are no alterations or modifications to be made. However if nomatches are found for the IP address, the information concerning theparticular IP address, the application using the gateway device from theparticular host and the information concerning the port type and subnetmask is obtained from the IP datagram and configuration information andused to build a new entry in the port-sharing table to be used for allfuture communications. The MTU or maximum transmission Unit size is alsodetermined. The MTU is the maximum data size allowable for processing.

The following tables depicts the information that is obtained from theIP datagram and configuration information, and the information returnedto the host and/or established to be used for future communications.FIGS. 7A and 7B show this exchange of information flow to and from thegateway. While FIG. 7A shows this exchange for the following tablesrepresented in this section, FIG. 7B is a similar counterpart showingthe flow for the alternate embodiment as described below.

Table 1A is composed of the information obtained at the onset of SETIPAddress command and Table 1B comprises of the returned information.

TABLE 1A SETIP Command Structure

Where: nnnn - Sequence Number Field - two byte field containing a S/390integer sequence counter. Each command initiator maintains its ownsequence count, which starts at zero for the first command, and isserially incremented (by one) for each subsequent command. The responsestring will contain the same sequence number echoed back. LT - Adaptertype code - one byte field indicating the adapter type code. 1 =Ethernet 2 = Token Ring 7 = FDDI LN - Relative adapter number - one bytefield indicating the relative adapter number. VER - 2 byte field -version supported for this command (valid entries are 4 (IP V4) or 6 (IPV6)). CNT - Count Field - 2 byte field (unsigned integer) contains thenumber of parameters that are included in the command data field. IPAddr - IP address of the connection. This is a 4 or 16 byte fielddepending on the value of the version id. (V4 = 4 bytes, V6 = 16 bytes).Netmask - The TCP/IP Netmask of this connection. This is a 4 or 16 bytefield depending on the value of the version id. (V4 = 4 bytes, V6 = 16bytes). MTU - The Maximum transmittal unit size (MTU) of thisconnection. This a 4 byte field stating the max frame size that can betransmitted on this LAN/WAN segment.

TABLE 1B SETIP Reply Structure

Where: nnnnn - Sequence Number Field - two byte field containing a S/390integer sequence counter. Each command initiator maintains its ownsequence count, which starts at zero for the first command, and isserially incremented (by one) for each subsequent command. The responsestring will contain the same sequence number echoed back. RC - Commandreturn code. 2 byte fieid indicating the return code status. RC values:

LT - Adapter type code - one byte field indicating the adapter typecode. 1 = Ethernet 2 = Token Ring 7 = FDDI LN - Relative adapternumber - one byte field indicating the relative adapter number. VER - 2byte field - version supported for this command (valid entries are 1(SNA), 4 (IP V4), or 6 (IP V6)). ASTS - 16 bit field - TCP/IP Assistssupported (information valid only in reply frames). The bit flelds aredefined as follows (bit on signifies supported) Assist List: ArpProcessing- bit0 (0x0001) Inbound Checksum Support- bit 1 (0x0002)Outbound Checksum Support- bit 2 (0x0004) IP Fragmentation/Reassembly-bit 3 (0x0008) Filtering- bit 4 (0x0010) IP V6 Support- bit 5 (0x0020)ASTE - 16 bit fieId TCP/IP Assists Enabled (information valid only inreply frames). CNT - Count Field - 2 byte field (unsigned integer)contains the number of parameters that are included in the command datafield. DATA - RC code dependent data.

QIPASST—Query IP Assist Function

One of the commands provided by the present invention is a SET IPAssist. The IP Assist command designed for high performance LAN/WANconnections allows the dynamic configuration of IP functions in gatewaydevices and enables virtual IP addressing. TCP-UDP/IP will use thiscommand to query the channel or integrated platform which TCP-UDP/IPfunctions on the device are available. This allows TCP-UDP/IP toindividually select which functions it desires to use. The SET IP Assist(SETASSTPARMS) function allows TCP/IP to support multiple devices whichin turn can support multiple levels of IP Assist functions. TCP/IP canspecify different IP functions for each configured IP address with theSET IP ASSIST function. This adds considerable flexibility to TCP/IP.Special IP ASSISTs which are more useful for specific IP addressesconfigured for Web Serving can specify specific IP ASSISTs which aredesigned for Web Serving.

FIG. 5 provides some of the functions supported and used by TCP/IP andon the OSA platform. These assist functions include ARP, InboundChecksum, Outbound Checksum and IP Fragmentation/Reassembly. The IPAssist functions are designed to shorten the Host code path length andimprove the performance of TCP/IP. By providing a command which can beused to query the communication adapters, individual IP sessions whichrun through the adapter can be setup to use the fast path and the otherIP sessions can use the normal path. Again a list of the functionsavailable is kept on the port-sharing table and those that becomeavailable or unavailable are masked off appropriately. In this way it iseasy to determine at once which functions are supported by the system atany one time very efficiently. The following tables highlight theinformation originally obtained (Table 2A) and information relayed backto the host (Table 2B). Note that the information provided in FIG. 5highlighting OSA supported functions ARP, Inbound Checksum, OutboundChecksum and IP Fragmentation/Reassembly are only for demonstrationpurposes. The set of functions can be customized to include more or lesselements selectively as applications require.

TABLE 2A QIPASST Command Structure

Where: nnnnn - Sequence Number Field - two byte field containing a S/390integer sequence counter. Each command initiator maintains its ownsequence count, which starts at zero for the first command, and isserially incremented (by one) for each subsequent command. The responsestring will contain the same sequence number echoed back. LT - Adaptertype code - one byte field indicating the adapter type code. 1 =Ethernet 2 = Token Ring 7 = FDDI LN - Relative adapter number - one bytefield indicating the relative adapter number. VER - 2 byte field -version supported for this command (valid entries are 4 (IP V4), or 6(IP V6)).

TABLE 2B FIG. 7-15 QUERYIP Reply Command Structure

Where: nnnnn - Sequence Number Field - two byte field containing a S/390integer sequence counter. Each command initiator maintains its ownsequence count, which starts at zero for the first command, and isserially incremented (by one) for each subsequent command. The responsestring will contain the same sequence number echoed back. RC - Commandreturn code. 2 byte field indicating the return code status. RC values:0x0000 = Success 0x0001 = Command Not Supported 0xE003 = Incorrect LANType or Number LT - Adapter type code - one byte field indicating theadapter type code. 1 = Ethernet 2 = Token Ring 7 = FDDI LN - Relativeadapter number - one byte field indicating the relative adapter number.VER - 2 byte fleld - version supported for this command (valid entriesare 4 (IP V4) or 6 (IP V6)). ASTS - 16 bit fleld TCP/IP Assistssupported (information valid only in reply frames). The bit flelds aredefined as follows (bit on signifies supported) Assist List: ArpProcessing - bit 0 (0x0001) Inbound Checksum Support - bit 1 (0x0002)Outbound Checksum Support - bit 2 (0x0004) IP Fragmentation/Reassembly -bit 3 (0x0008) Filtering - bit4 (0x0010) IP V6 Support - bit 5 (0x0020)ASTH - 16 bit fleld - TCP/IP Assists Enabled (information valid only inreply frames).

SETASSTPARMS—Set IP Assist (Parameters)

The SETASSTPARMS command is used by the host IP stack and all the IPapplications (i.e. TCP/IP, UDP/IP etc.) to enable the particular assistsdesired and to specify the parameters needed by the particular assiststhat are being implemented in the channel, integrated or OSA specificplatforms. Examples of these parameters is the setting of the size ofthe ARP Cache, or the protocols that will be filtered if BroadcastFiltering is implemented. When used with an OSA adapter, the OSA adapterwill just discard the broadcast packet when it has been received. The IPprotocols include RIP (Routing Information Protocol, SNMP (SimpleNetwork Management Protocol) and BGP (Border Gateway Protocol). Thiscommand allows the user not only to query about the functions that areavailable but to selectively pick and choose these functions. Tables 3Aand 3B are representative of the information obtained and informationreturned respectively. Tables 3C and 3D represent some of the commandsavailable and the responses returned.

TABLE 3A FIG. 7-16 SETASSTPARMS Command Structure

Where: nnnnn - Sequence Number Field - two byte field containing a S/390integer sequence counter. Each command initiator maintains its ownsequence count, which starts at zero for the first command, and isserially incremented (by one) for each subsequent command. The responsestring will contain the same sequence number echoed back. LT - Adaptertype code - one byte field indicating the adapter type code. 1 =Ethernet 2 = Token Ring 7 = FDDI LN - Relative adapter number - one bytefield indicating the relative adapter number. VER - 2 byte field -version supported for this command (valid entries are 4 (IP V4) or 6 (IPV6)). Assist Number -

Assist Options - Assist Specific - refer to table below AssistParameters - Assist Specific - refer to table below

TABLE 3B SETASSTPARMS Reply Command Structure

Where: nnnnn - Sequence Number Field - two byte field containing a S/390integer sequence counter. Each command initiator maintains its ownsequence count, which starts at zero for the first command, and isserially incremented (by one) for each subsequent command. The responsestring will contain the same sequence number echoed back RC - Commandreturn code. 2 byte field indicating the return code status. RC values:0x0000 = Success 0x0001 = Command Not Supported 0xE003 = Incorrect LANType or Number LT - Adapter type code - one byte field indicating theadapter type code. 1 = Ethernet 2 = Token Ring 7 = FDDI LN - Relativeadapter number - one byte field indicating the relative adapter number.VER - 2 byte field - version supported for this command (valid entriesare 4 (I PV4) or 6 (IP V6)). ASTS - 16 bit field - TCP/IP Assistssupported (information valid only in reply frames). The bit fields aredefined as follows (bit on signifies supported) Assist List: ArpProcessing - bit 0 (0x0001) Inbound Checksum Support - bit 1 (0x0002)Outbound Checksum Support - bit 2 (0x0004) IP Fragmentation Reassembly -bit 3 (0x0008) Filtering - bit 4 (0x0010) IP V6 Support - bit 5 (0x0020)ASTE - 16 bit field - TCP/IP Assists Enabled (information valid only inreply frames). ASN - 2 byte field - Assist Number ASO - 2 byte field -Assist Option RC - 4 byte field - Return Code - 0x00000000 - SuccessAnything else - command specific failure Data - Assist specific data

TABLE 3C Assist Assist Assist Command Number Command Assist CommandDescription Parameters ARP 0x0001 Start Assist None (0x0001) 0x0002 StopAssist None 0x0003 Set Number of ARP Cache 4 byte field = Entries(Default = 256) number of entries 0x0004 Query ARP Cache Table - Nonereturns all entries in ARP Cache 0x0005 Add ARP Cache Entry 4 or 16 bytefield = IP address of entry you want to add 0x0006 Remove ARP CacheEntry 4 or 16 byte field = IP address of entry you want to remove 0x0007Flush ARP Table - all ARP None Cache Entries are deleted Inbound 0x0001Start Assist None CheckSum 0x0002 Stop Assist None Support 0x0003 EnableCheckSum Frame None (0x0002) Types (Bit on enables feature) Bit 0 -Enable IP Frame CheckSumming Bit 1 - Enable ICMP Frame CheckSumming Bit2 - Enable UDP Frame CheckSumming Bit 3 - Enable TCP Frame CheckSummingBits 4-31 - reserved (set to zero) Outbound 0x0001 Start Assist NoneCheckSum 0x0002 Stop Assist None Support 0x0003 Enable CheckSum FrameNone (0x0004) Types (Bit on enables feature) Bit 0 - Enable IP FrameCheckSumming Bit 1 - Enable ICMP Frame CheckSumming Bit 2 - Enable UDPFrame ChecKSumming Bit 3 - Enable TCP Frame CheckSumming Bits 4-31 -reserved (set to zero) IP 0x0001 Start Assist None Frag/ 0x0002 StopAssist None Reassmble Support (0x0008) Filtering 0x0001 Start AssistNone Support 0x0002 Stop Assist None (0x0010) 0x0003 What Frames toFilter (32 Bit None field) Turn bit on to enable filtering) Bit 0 - ARPFrames (This bit is turned on automatically if the ARP Assist isenabled) Bit 1 - RARP Frames Bit 2 - ICMP Frames Bit 3 - IP Frames Bit4 - IPX/SPX Frames Bit 5 - RIP Frames Bit 6 - BGP Frames Bit 7 - UDPFrames Bit 8 - TCP Frames Bit 9 - SNMP Frames Bit 10 - Mutlicast FramesBit 11 - BroadCast Frames Bit 12-31 - Reserved IPV6 0x0001 Start AssistNone Support 0x0002 Stop Assist None (0x0020) 0x0003 What Functions toSupport None (32 Bit field) (Turn bit on to enable) Bit 0 - Allow V6Traffic Bit 1 - Allow V4 Traffic Bit 2 - Translate V4 to V6 Model Bit3 - Translate V6 to V4 Model Bit 4 -31 - Reserved

TABLE 3D SETASSTPARMS Reply Command Options Assist Data (Reply) - AssistNumber Assist Command Assist Command Description (least significant 2bytes) ARP 0x0001 Start Assist RC - 0x0000 - Success (0x0001) 0x0001 -Failed 0x0002 - Not Supported Data - None 0x0002 Stop Assist RC -0x0000 - Success 0x0001 - Failed 0x0002 - Not Supported Data - None0x0003 Set Number of ARP Cache Entries (Default = 256) RC - 0x0000 -Success 0x0001 - Failed 0x0002 - Not Supported 0x0003 - Out of RangeData - if RC = 0x0003 return 4 bytes - max number of entries supported0x0004 Query ARP Cache Table - returns all entries in RC - 0x0000 -Success ARP Cache 0x0001 - Failed 0x0002 - Not Supported Data - if nonfailing RC - returns ARP Cache Table 0x0005 Add ARP Cache Entry RC -0x0000 - Success 0x0001 - Failed 0x0002 - Not Supported Data - returnsARP Cache Entry 0x0006 Remove ARP Cache Entry RC - 0x0000 - Success0x0001 - Failed 0x0002 - Not Supported Data - returns ARP Cache Entry0x0007 Flush ARP Table - all ARP Cache Entries are RC - 0x0000 - Successdeleted 0x0001 - Failed 0x0002 - Not Supported Data - None Inbound0x0001 Start Assist RC - 0x0000 - Success CheckSum 0x0001 - FailedSupport 0x0002 - Not Supported (0x0002) Data - None 0x0002 Stop AssistRC - 0x0000 - Success 0x0001 - Failed 0x0002 - Not Supported Data - None0x0003 Enable CheckSum Frame Types (Bit on enables RC - 0x0000 - Successfeature) 0x0001 - Failed Bit 0 -Enable IP Frame CheckSumming 0x0002 -Not Supported Bit 1 - Enable ICMP Frame CheckSumming Data - 4 bytes withleast 4 Bit 2 - Enable UDP Frame CheckSumming significant bitsrepresenting Bit 3 - Enable TCP Frame CheckSumming what CheckSummingsupport Bit 4-31 - reserved (set to zero) is available OutBound 0x0001Start Assist RC - 0x0000 - Success CheckSum 0x0001 - Failed Support0x0002 - Not Supported (0x0004) Data - None 0x0002 Stop Assist RC -0x0000 - Success 0x0001 - Failed 0x0002 - Not Supported Data - None0x0003 Enable CheckSum Frame Types (Bit on enables RC - 0x0000 - Successfeature) 0x0001 - Failed Bit 0 - Enable IP Frame CheckSumming 0x0002 -Not Supported Bit 1 - Enable ICMP Frame CheckSumming Data - 4 bytes withleast 4 Bit 2 - Enable UDP Frame CheckSumming significant bitsrepresenting Bit 3 - Enable TCP Frame CheckSumming what CheckSummingsupport Bits 4-31 - reserved (set to zero) is available IP 0x0001 StartAssist RC - 0x0000 - Success Frag/ 0x0001 - Failed Reassmble 0x0002 -Not Supported Support Data - None (0x0008) 0x0002 Stop Assist RC -0x0000 - Success 0x001 - Failed 0x0002 - Not Supported Data - NoneFiltering 0x0001 Start Assist RC - 0x000 - Success Support 0x0001 -Failed (0x0010) 0x0002 - Not Supported Data - None 0x0002 Stop AssistRC - 0x0000 - Success 0x0001 - Failed 0x0002 - Not Supported Data - None0x0003 What Frames to Filter (32 Bit field) RC - 0x0000 - Success (Turnbit on to enable filtering) 0x0001 - Failed 0x0002 - Not Supported Bit0 - ARP Frames (This bit is turned on Data - 4 bytes with least 12automatically if the ARP Assist significant bits representing isenabled) what Filtering support is Bit 1 - RARP Frames available Bit 2 -ICMP Frames Bit 3 - IP Frames Bit 4 - IPX-SPX Frames Bit 5 - RIP FramesBit 6 - BGP Frames Bit 7 - UDP Frames Bit 8 - TCP Frames Bit 9 - SNMPFrames Bit 10 - Mutlicast Frames Bit 11 - BroadCast Frames Bit 12-31 -Reserved IP V6 0x0001 Start Assist RC - 0x0000 - Success Support0x0001 - Failed (0x0020) 0x0002 - Not Supported Data - None 0x0002 StopAssist RC - 0x0000 - Success 0x0001 - Failed 0x0002 - Not SupportedData - None 0x0003 What Functions to Support (32 Bit field) RC -0x0000 - Success (Turn bit on to enable) 0x0001 - Failed Bit 0 - AllowV6 Traffic 0x0002 - Not Supported Bit 1 - Allow V4 Traffic Data - 4bytes with least 4 Bit 2 - Translate V4 to V6 Model significant bitsrepresenting Bit 3 - Translate V6 to V4 Model what function support isBit 4-31 Reserved available

Multi-Path Channels—An Alternate Embodiment

MPC or multi-path channel protocol is a highly efficient data transferinterface developed to replace LCS by IBM Corp. of Armonk, N.Y. MPC canbe implemented in the TCP/IP or VTAM layer; it can also be implementedusing Novell based systems. In the existing systems when Host A wants tosend data to the gateway or another host, it will wait and collect allinformation that has to be sent in preselected sizes. This waiting andgrouping of data is called “blocking”. On the receiving side, thisblocked data has to be “deblocked” to distinguish between the individualcommands or data.

The existing LCS protocol provides an efficient method of transferringdata across the I/O subsystem by blocking multiple LAN frames togetherin one long chain. However, to provide this interface the LCS protocolis required to use the host processor to copy all the LAN Media Headersand all the application data into one contiguous block before performingthe data transfer across the I/O subsystem. Also the LCS must prependeach LAN frame in the block with a four byte LCS header. This header isneeded by the “deblocker” application running on the channel attachedplatform. The “deblocker” application uses the header to remove theindividual LAN frames from the LCS block and send them to the LAN. Thismakes very inefficient use of the host's memory and creates extralatency for the user data. The current LCS interface also requires thedevice drivers to build the LAN Media Headers. The data passed to LCSmust be in the exact format of the data which is to be transferred tothe LAN. This requires all applications using the LAN interface to knowwhich LAN type the data is being transferred to along with thedestination LAN MAC addresses. One unique device driver must be writtenfor each LAN type to which the application is connected.

The MPC protocol uses a new type of “blocked” data stream known asDiscontiguous Protocol Data Units or DPDUs. This new data streaminterface allows the header or control information to be in a separatememory area from the user data as it is transferred to the I/Osubsystem. This eliminates the need to copy all the LAN media Headersand the application data into one contiguous area. For VTAMapplications, a Macro interface has been provided to use when sendingdata across the MPC connection. The interface allows the application tospecify a buffer list. Each entry in the buffer list corresponds to oneportion of the discontiguous user data. MPC uses Protocol Data Unit orPDU headers to point at the various portions of the discontiguous userdata. Each PDU will contain a list of the PDU elements. Each PDU elementwill point to one of the entries in the buffer list.

To address the special needs arising from the new MPC protocol manner ofhandling data streams, an alternate embodiment of the present inventionis required and presented here. The three command concepts explainedearlier, namely SET IP Address, Query IP and Set IP Assist (parameters)are adjusted to function with the MPC's new requirement. The result iscomplementary functions SET IPX Address, Query IPX and SETASSTPARMS IPX.

Similar to SET IP Address command, the Set IPX Address command (usedprimarily but not exclusively with Novell's IPX communication protocol)also to associate an IP address with a specific user session. Thecommand is initiated by the user. Once the command is received, thegateway device quickly searches its existing port-sharing tables to seeif the particular IP address is included or not, and alterations,additions or modifications are made if an exact match is not found.However, in the SET IPX Address scenario the only information providedto the gateway device is the LAN port number and id. All otherinformation including a MAC address (as one is necessary in thisscenario), MTU size and even the LAN type is provided by the gatewaydevice itself from the port-sharing tables. The following tables providethe specifics of the exchange of information between the host and thegateway device. Notice that all necessary headers including a MAC Headeris either dissected or returned by the gateway device as required. TableX1 A and X1 B below shows the IPX command requirements and returnedinformation.

TABLE X1 A SETIPX Command Format

Where: CI SETIPX command nnnn Sequence Number filed LN LAN Number to beused by IPX on the OSA Adapter MTU IPX Maximum Transmission Unit forthis connection. This is a four byte field stating the maximum framesize which can be transmitted on this LAN/WAN segment. A value of0xFFFFFFFF implies the MTU value used will be the returned by OSA on theSETIPX response shown below.

TABLE X1 B The OSA Command Response Format is as follows:

Where: nnnn Sequence number matching the SETIPX request RC Return code(Status) from OSA Adapter LT LAN Type associated with the LAN Portselected on the SETIPX request LN LAN Number which was specified withthe SETIPX request MAC MAC Address of OSA LAN Port MTU Supported MTUvalue on the OSA adapter

Tables X1 C and X1 D below reflect two new sub-command functions the IPXBind and UNBIND. Binding is a function that allows the supporting ofdifferent LAN types on one computing network environment. The Bindfunction allows the association of particular LAN frame types to agateway or the physical port. Unbind function is used when a host IPXconnection terminates or is shutdown. The Bind command allows one NovellIPX device driver running on the host to support multiple LAN typesalong with multiple frame types within a specific LAN type. Prior tothis implementation, one device driver was necessary for each LAN typeand each frame type within a specific LAN type. For example, one devicedriver can now support an Ethernet-SNAP and Ethernet-802.2 frame type.

IPXBIND

The IPX BIND command is used to BIND a Frame Type to the OSA LAN Port.

The Command Format is as follows:

TABLE X1 C

Where: C2 IPX BIND command nnnn Sequence Number filed LT LAN Type ofport LN LAN Number SAP Novell's Service Advertising Protocol. Thisprotocol is used by a Client machine to determine what servers areavailable on the Network.

IPXUNBIND

TABLE X1 D

Where: C3 IPX UNBIND Command nnnn Sequence Number filed RC Return Codereturned from OSA LT LAN Type of port LN LAN Number

Subsequent Bind and Unbind commands as reflected in tables X1 E and X1 Fbelow are also used to add even additional information, for exampleadditional SAP parameters. These functions are used in a manner similarto the original bind and unbind function.

IPXSUBBIND

The IPX Subsequent BIND command is used to specify additional SAPinformation to the OSA adapter. The Subsequent BIND command may or maynot immediately follow the IPX BIND command. Once the Subsequent BINDcommand has been processed, IPX RIP and SAP frames will be forwarded tothe operating system (MVS).

The format of the IPX Subsequent BIND command is as follows:

TABLE X1 E

Where: C4 IPX Subsequent Bind Command nnnn Sequence Number filed RCReturn Code returned from OSA LT LAN Type of port LN LAN Number More SAPMore SAP information

IPXSUBUNBIND

TABLE X1 F

Where: C5 IPX Subsequent UNBIND Network Command nnnn Sequence Numberfiled RC Return Code returned from OSA LT LAN Type of port LN LAN Number

IPX Bind net command (table X1 G) reflects a command used to passnetwork numbers associated with the operating system to thecommunication platform. Once a Network Number is specified, then all IPXtraffic will be allowed to flow through the IPX connection. The networknumber will be used to route all non-RIP and non-SAP frames to theproper IPX connection. (RIP and SAP being two functions that aresupported in this embodiment.)

FIG. 7B shows the flow of data back and forth from the gateway devicefor the functions described. Below, Table X1 G shows an example of thisfor MVS operating system and OSA platform. IPX Unbind net, shown attable X1 H, below is similar to other unbind commands.

IPXBINDNET

The IPX BIND Network Command is used to pass the IPX Network Numbersassociated with the MVS Netware Stack to the OSA adapter. Once thiscommand has been processed all IPX frames can be forwarded to the MVSIPX Stack(s).

The format of the IPX BIND Network command is as follows:

TABLE X1 G

Where: C6 IPX BIND Network Command nnnn Sequence Number filed RC ReturnCode returned from OSA LT LAN Type of port LN LAN Number CNT The countof Network numbers in the Data field NN IPX Network Number(s). EachNetwork Number is 4 bytes is length. The CNT field indicates the numberof Network Numbers present in this field.

IPXUNBINDNET

TABLE X1 H

Where: C7 IPX UNBIND Network Command nnnn Sequence Number filed RCReturn Code returned from OSA LT LAN Type of port LN LAN Number

The SET IPX Assist function is also similar to the IP Assist commandfunctions in that they are both designed for high performance LAN/WANconnections and allow the dynamic configuration of IPX address ingateway devices. As stated before MPC works both with the TCP/IP andother communications protocol including NetBios as well as the Novelprotocol stacks and drivers. As a consequence the number of functionsavailable for the user is more involved. However, again through thepre-established port-sharing tables, it is determined and known to thegateway device as which functions are supported by the device. The setof functions are different in this section and RIP and SAP functions areadded to the list of functions available, while other functionsspecified before with the exception of broadcast filtering may not beavailable.

Table X2 is reflective of this.

Request Format

Reply Format

Where: nnnnn - Sequence Number Field - two byte field containing a S/390Integer Sequence LT - Adapter type code - one byte field indicating theadapter type code. 1 = Ethernet/Fast Ethernet 2 = Token Ring 7 = FDDILN - Relative adapter number - one byte field indicating the relativeadapter number. VER - 2 byte field - IPX Version Supported RC - Commandreturn code. 2 byte field indicating the return code status. RC values:0x0000 = Success 0x0001 = Command Not Supported 0xE003 = Incorrect LANType or Number ASTS - 16 bit field - IPX Assists supported (informationvalid only in reply frames). The bit fields are defined as follows (biton signifies supported) Assist List: RIP Assist - bit 0 (0x0001) SAPAssist - bit 1 (0x0002) Frame Filtering - bit 2 (0x0004) Host to HostRouting Setup - bit 3 (0x0008) Extended IPX Version Support - bit 4(0x0010) (Bits 5-15 are reserved for future use) ASTE - 16 bit field -IPX Assists Enabled (information valid only in reply frames). FIG. X2 -QIPXASST - Request and Reply Command Format

The SETASSTPARMS IPX command is used in a similar manner to its IPcounterpart. It is designed to allow the user to select among theappropriately available functions. As before, this command allows theuser not only to query about the functions that are available but toselectively pick and choose these functions. Tables X3 is representativeof the information obtained and information returned respectively.

Request Format

Reply Format

Where: nnnnn - Sequence Number Field - two byte field containing a S/390Integer Sequence LT - Adapter type code - one byte field indicating theadapter type code. 1 = Ethernet/Fast Ethernet 2 = Token Ring 7 = FDDILN - Relative adapter number - one byte field indicating the relativeadapter number. VER - 2 byte field - IPX/SPX Version supported. AssistsSupported (ASTS) - Assist Enabled (ASTE) - 16 bit Fields

Assist Options - Assist Specific Assist Parameters - Assist SpecificASN - 2 byte field - Assist Number ASO - 2 byte field - Assist OptionRC - Command return code. 2 byte field indicating the return code status0x0000 = Success 0x0001 = Command Not Supported 0xE003 = Incorrect LANType or Number Data - Assist specific data FIG. X3 - SETIPXASSTPARMSReply and Request Command Format

In closing of this section, it should be noted that the new routingmechanism suggested by the teachings of the present invention isworkable for the MPC protocol as well. Again, through the port-sharingtables it is possible to route messages directly from Host A to Host Bwithout having to access the LAN. It is as before the gateway devicethat controls and monitors the configurations of the host devices. Asbefore, this routing mechanism can be implemented in a loosely coupledenvironment, such as a Sysplex, for sending any type of data between anytwo hosts and especially without involving any LAN/WAN connections.

Blocking IP Datagrams in an MPC Point-to-point Environment

FIG. 6 shows the blocking of data in the existing systems. Block Header610 shows the start of a new data batch. Each block header 610 isusually followed by the appropriate MAC Header and LLC shown at 612 and614. The Protocol header and the Protocol data follow as shown in 616and 618. A new block of data is shown at 620 and 630. Usually theapplications receive user data which is to be sent to the LAN in a databuffer. The applications send the user data to the protocol layer. UsingMPC, the protocol layers device drivers can now build the LAN Mediaheaders in a separate buffer area and pass a buffer list to the MPCMacro interface. MPC will then build one PDU with two PDU elements torepresent the LAN frame. This design, however, also creates someinefficiencies. First, each PDU header built by the VTAM or similarprotocols is lengthy, usually having a length of 28 bytes plus the PDUelement headers are each 8 bytes in length, normally. This translatesinto a confined, usually 44 (28+8+8) header being built for each LANframe being sent by the application. This is compared to the 4 byte LCSheader associated with each LAN frame. Second, the protocol stacks muststill build the LAN Media headers and be knowledgeable of the LAN Mediato which the data is being transmitted. One unique Device Driver must bewritten on the Host to support each unique LAN type. LCS has the samerequirement. Building the LAN Media headers requires the allocation of aspecial buffer and the moving of the LAN specific data into this buffer.MPC must also build a separate PDU element for the headers.

The present invention also teaches an interface layer composed ofsoftware to be placed between the protocol stacks and MPC. This layerhas a timer to wait for data from the protocol stacks. As data buffersare received, a buffer list is assembled. The buffer list contains oneentry for each data buffer received. After the timer expires, the bufferlist is then transferred to the MPC layer. The MPC layer then places theentire buffer list which contains multiple data buffers from a protocolin one PDU. The data will be transmitted across the I/O Subsystem in oneCCW chain, arriving at the channel attached processor as one “block”.

Since the data contained inside the one “block” received from MPC codecontains application data from a protocol stack, the protocol headerscontain the length of each data element. The “deblocker” code running onthe channel attached processor uses the length fields in the protocolheaders to determine the offset of the next data element in the block.This eliminates the need for a special header to point at the next dataelement which is used by the LCS protocol.

The blocking of multiple protocol data elements in one PDU also improvesthe efficiency of the data transfer. In this case, only one PDU headerneeds to be processed for one group of “n” protocol data elements.Previously, one PDU header needed to be processed for each protocol dataelement.

To further improve the efficiency, the requirement of building LAN Mediaheaders can also be removed with the present invention, from theprotocol device drivers. The protocol device drivers just append thedestination address on the local LAN as required for each specificprotocol. The protocol stacks no longer need to have a unique devicedriver for each unique LAN connection. One device driver can now be usedfor all LAN connections. This requirement was removed by placing code inthe channel attached platform which builds the LAN Media headers. TheLAN media headers are built as the protocol data is removed from theblock by the “deblocker” code.

While the invention has been described in detail herein in accordancewith certain preferred embodiments thereof, many modifications andchanges therein may be effected by those skilled in the art.Accordingly, it is intended by the appended claims to cover all suchmodifications and changes as fall within the true spirit and scope ofthe invention.

We claim:
 1. In a computing environment having a plurality of hosts, amethod of establishing communication between a first initiating host anda second receiving host, said computing network environment also havingat least one local area network, said method comprising the steps of:providing a gateway device and electronically connecting said gatewaydevice to at least one initiating host, said host(s) being potentiallyassociated with one or more local area networks; electronicallyconnecting said gateway device also to at least one receivingdestination host, said host(s) being potentially associated with one ormore local area network(s); providing in said gateway deviceconfiguration information, information used for communication,information pertaining to functions supported by said gateway device,and information pertaining to functions provided by said gateway devicefor each host, as said information relates to said hosts and any oftheir potentially associated local area networks; and establishing saidgateway device as central point of communication between all hosts sothat said destination host(s) can obtain all necessary information aboutsaid initiating host(s) directly via said gateway device withoutinvolving any of said potentially associated local area network(s). 2.The method of claim 1, wherein said information used for communicationincludes communication platform, communication protocol and local areanetwork type information.
 3. The method of claim 2, wherein saidcommunication platform is a channel attached platform.
 4. The method ofclaim 2, wherein said communication platform is an integrated platform.5. The method of claim 2, wherein said communication platform is an opensystems adapter platform.
 6. The method of claim 1, wherein saidcomputing environment uses TCP/IP communication protocol.
 7. The methodof claim 1, wherein said computing environment uses UDP/IP communicationprotocol.
 8. The method of claim 1, wherein a plurality of local areanetworks are associated with said hosts and each said local area networkare of a different type and use a different communication protocol. 9.The method of claim 8, wherein said local area network(s) are ofdifferent type with associated independent communication platforms. 10.The method of claim 1, wherein said gateway device modifies and altersits information based on addition, deletion or disablement of said hostsand any of their associated local area networks.
 11. The method of claim10, wherein said communication connections between said hosts and any oftheir associated local area networks and said gateway device ismonitored by said gateway device at preselected intervals and anyinactive or problematic connections are reported and appropriatemodifications made.
 12. The method of claim 1, wherein one or more ofsaid hosts are potentially connected to at least one wide area network.13. The method of claim 1, wherein said gateway device uses LAN ChannelStation communication protocol.
 14. The method of claim 1, wherein saidcomputer environment uses a Multi-path channel communication protocol.15. The method of claim 14, wherein said communication platform is anintegrated platform.
 16. The method of claim 14, wherein saidcommunication platform is an open systems adapter platform.
 17. Themethod of claim 14, wherein said computing environment uses Novell IPXcommunication protocol.
 18. The method of claim 14, wherein saidcomputing environment uses VTAM communication protocol.
 19. The methodof claim 14, wherein any associated local area network(s) are ofdifferent type and with different and independent communicationplatforms.
 20. The method of claim 14, wherein one or more of said hostsare also connected to at least one wide area network.
 21. In a computingenvironment having a plurality of hosts, an apparatus used forestablishing communication between a first initiating host and a secondreceiving host, said computing network environment also having at leastone local area network, said apparatus comprising: a gateway deviceelectronically connected to at least one initiating host, said host(s)being potentially associated with one or more local area networks; saidgateway device also being in electronic communication with at least onereceiving destination host, said host(s) being potentially associatedwith one or more local area network(s); a central location provided insaid gateway device for retaining configuration information, informationused for communication, information pertaining to functions supported bysaid gateway device, and information pertaining to functions provided bysaid gateway device for each of said hosts, as said information relatesto said hosts and any of their potentially associated local areanetworks; means for establishing said gateway device as central point ofcommunication between all hosts so that said destination host(s) canobtain all necessary information about said initiating host(s) directlyvia said gateway device without involving any of said potentiallyassociated local area network(s).
 22. The apparatus of claim 21, whereinsaid information used for communication includes communication platform,communication protocol and local area network type information.
 23. Theapparatus of claim 22, wherein said communication platform is anintegrated platform.
 24. The apparatus of claim 22, wherein saidcommunication platform is an open systems adapter platform.
 25. Theapparatus of claim 22, wherein said computing environment uses TCP/IPcommunication protocol.
 26. The apparatus of claim 21, wherein saidcomputer environment uses a Multi-path channel communication protocol.27. The apparatus of claim 26, wherein said communication platform is anintegrated platform.
 28. The apparatus of claim 26, wherein saidcommunication platform is an open systems adapter platform.
 29. Theapparatus of claim 26, wherein said computing environment uses TCP/IPcommunication protocol.
 30. The apparatus of claim 21, wherein saidgateway device modifies and alters its information based on addition,deletion or disablement of said hosts and any of their associated localarea networks.